Efficacy, safety, and immunogenicity of the AS01

Summary

In a multinational, phase 3, randomized, observer-blind trial in adults ≥60 years, a single dose of RSVPreF3 OA conferred 62.9% cumulative efficacy against RSV-LRTD over three consecutive seasons, with efficacy against both RSV A and B. Protection waned over time, and revaccination at one year produced efficacy in the same range as a single dose. Safety was clinically acceptable.

Key Findings

• Single-dose RSVPreF3 OA showed 62.9% cumulative efficacy against RSV-LRTD over three seasons (median follow-up 30.6 months).
• Efficacy was demonstrated against both RSV A (69.8%) and RSV B (58.6%) related LRTD.
• Efficacy waned over time; revaccination at 1 year yielded efficacy within the same range as a single dose; safety profile was acceptable with <1% serious adverse events judged related.

Clinical Implications

Supports adoption of RSVPreF3 OA for adults ≥60 with expected protection across at least three seasons; clinicians should anticipate waning and watch for forthcoming guidance on optimal revaccination timing.

Limitations

• Efficacy waned over time; optimal revaccination interval remains undefined.
• Severe outcomes and subgroup safety signals are not fully detailed in the abstract and require full-text appraisal.

Future Directions

Define optimal revaccination schedules (interval and target subgroups), assess durability against severe RSV-LRTD and hospitalization, and evaluate coadministration with other seasonal vaccines.